An aluminum deposited film is broadly used as a composite of electrodes and dielectrics for capacitors. Since aluminum is not good in chemical stability, however, an aluminum deposited layer generally lacks moisture resistance. Namely, because an aluminum deposited layer has low durability with respect to corrosion in a high-temperature and high-humidity atmosphere, the layer is liable to lose its function required as electrodes of a capacitor. Therefore, in a capacitor using such an aluminum deposited layer, generally its encapsulation is reinforced according to its environment in order to overcome the above defect. However, this reinforcement is often insufficient.
In a case where a deposited layer cannot be formed if the deposition material is directly deposited such as a case where zinc is attempted to be deposited directly on a polypropylene film or a paper, or in a case where formation of a deposited layer is slow and therefore lacks industrial productivity, a process for assisting the formation of the deposited layer by predepositing a metal such as copper or silver which is to become a nuclei for the formation of the zinc deposited layer (so-called, nucleation) is known, for example, as disclosed in JP-A-SHO-58-16415. However, the object, operation and advantage of nucleation are quite different from those of the present invention. Actually, even if nucleation is performed when zinc is deposited, increase of corrosion resistance of the deposited layer in a high-temperature and high-humidity atmosphere, as in the present invention, cannot be achieved.